1. Field of the Invention
This application claims the benefit of priority under 35 U.S.C. §119 of EP Application 05106198.4, filed Jul. 7, 2005, the contents of which are hereby incorporated by reference.
The invention relates to a method for the automated handling of a fluid biological sample in an analytical instrument in the field of nucleic acid purification and amplification.
The invention further relates to a container and a tube suitable for the use in an analytical instrument, wherein a fluid biological sample is handled automatically as well as the instrument capable of handling and processing the fluid biological sample.
Moreover, the invention relates to a system capable of analyzing a biological sample by utilizing an instrument for the automated handling of a liquid in combination with a container in which the biological sample is processed.
Additionally, the invention relates to a method for the production of a container consisting of three plastic materials using the so-called multi component injection molding technology which allows the manufacturing of a product with different materials in one mold.
2. Description of the Related Art
The polymerase chain reaction (PCR) is an important and widespread method for amplification and analysis of nucleic acids. For performing PCR reactions reaction vessels have to fulfill a number of requirements. Vessels have to be tightly dosed during PCR reaction to avoid evaporation of liquid from the vessel. Furthermore, the temperature of the liquid inside the vessel has to promptly follow the outside default temperature given by a heating and/or cooling installation stipulating certain thermal conduction properties upon the vessel material. In specific PCR applications optical measurements are carried out during the course of the amplification leading to particular optical requisites of the vessel material regarding transparency and auto-fluorescence.
For PCR applications a variety of embodiments for vessels are common. Whereas most of them exhibit a similar shape, namely, a tube comprising a reversibly closable opening on the one end and a conically tapered permanently dosed second end, several embodiments regarding the closure, the spacial alignment and/or the combination of tubes are known. Thus, closures may be firmly attached to the tube or may be provided by a separate cap portion. Furthermore, besides their use as single vessels particular vessels may be combined and arranged to form plates comprising 96 or 384 cavities or strips comprising 6 or 8 tubes.
Such an arrangement of reaction vessels is described in EP 0642828, wherein a first part comprising reaction vessels of identical shape and dimension set up annularly and a second part comprising closures suitable for closing the reaction vessels gas-tightly also arranged annularly form a disposable arrangement of reaction vessels for carrying out temperature cycling of a liquid mixture. While these closures are placed into the openings to tightly seal the tube,
EP 0907083 displays a sample cup, which can be closed by a removable and screwable cap. Another vessel systems for treating and/or storing liquids is disclosed in US 20040234422 comprising a two-dimensional vessel arrangement with a plurality of vessels which are open at the top and which are interconnected to form a unit, and a two-dimensional closure arrangement which has an arrangement of closure elements corresponding to the vessel arrangement and by means of which the openings of the vessels can be closed.
Disposable polypropylene tubes for performing PCR typically have a lower conical portion and an upper cylindrical portion, wherein the lower portion contacts a correspondingly shaped hole in a heating block and has a substantially thinner wall than that of the upper portion of the tube. EP 1275438 discloses that the wall thickness of the conical section is in the range from 0.009 to 0.012 inches (0.2286 to 0.3048 mm) plus or minus 0.001 inches (0.0254 mm) with 0.012 inches (0.3048 mm) being the mostly preferred embodiment, while the wall angle relative to the longitudinal axis of the tube is typically 17° in the lower conical portion.
U.S. Pat. No. 5,382,408 discloses a micro-centrifuge tube having a container having a round opening and a frictionally seated lid being dimensioned to corer the opening and hingedly connected to the container. The lid has a lid extension extending upwardly from the lid surface and outwardly away from the hinge in such a manner which allows the lid to be unseated and moved from the opening of the container. Said frictionally seated lid has the disadvantage that the retention force of the lid on the tube is mainly depending on the diameter of the annular lid seal (on the underside of the lid) respectively on the diameter of the round opening of the micro-centrifuge tube and tends to vary, which is typical for injection molded parts. This might become even a major disadvantage when an internal pressure in the tube causes a force against the lid.
U.S. Pat. No. 5,577,626 disclose a closure having a base for attachment to a container at the opening and a lid hingedly connected to the base. The lid has an outwardly projecting engaging member whereby the user can release the latch and apply a force to the engaging member to lift the lid via the member. However, such closures are not useful for automated opening the lid as it requires two simultaneous movements: release of the latch and at the same time lift the lid via member. After a first little move of the lid, the object releasing the latch has to remove, which represents a further inconvenience for automated opening.
As automatic preparation and processing of biological samples is advantageous in many cases and becomes increasingly important, many PCR tubes available are adapted to the needs of fully automated procedures in robotic apparatuses. However, only few PCR vessels are capable of being fully automatically closable. EP 0907083 discloses such a vessel and an apparatus for automatically handling sample cups dosed with a screwable cap, wherein the apparatus is characterized in that it comprises a rotatable gripper tool apt to enter and engage with a recess of a vessel cap to form a connection which can be locked by rotating the gripper tool in a first sense and unlocked by rotating the gripper tool in a second sense opposite to the first. Besides, U.S. Pat. No. 5,578,494 describes a method for opening and closing a cap pivotally mounted on a container for storing reagents for the use in an automated analytical instrument by an actuating device.
All of these embodiments for the fully automated opening and closing of vessels have the common disadvantage, that there is one single closure for each single opening. Thus, in fully automated processes a multitude of single movements have to be performed leading to an increased complexity of the diagnostic process and thereby to decreased reliability. Moreover, with increasing complexity and increasing number of single movements the risk of spilling of liquid from the vessel drastically increases. Another disadvantage of these embodiments is speed and low operational capacity of automated processes as every single tube has to be opened successively. Furthermore, common PCR vessels applicable for fully automated closure either comprise screw tops or bayonet sockets demanding a robotic capable of rotary motions, which constructively is very complex and costly.
Furthermore, the problem of providing a sealing device to form a gas-tight seal for the efficient performance of analytical techniques such as the polymerase chain reaction has been addressed in U.S. Pat. No. 5,721,136 describing a multilayer composite sheet of material seals consisting of an elastically or inelastically deformable sealing layer having a tacky surface calendared or cast onto a relatively thin backing layer made up from any substance with low permeability to water vapor. This multilayer composite sheet may be placed over the openings of one or more reaction vessels in order to simultaneously seal one or more vessels for thermal cycling. Besides, EP 0836884 describes a seal for one or more vessels consisting of two elastic components, wherein a first seal provides an inner fluid-tight closure and a second outer closure provides a pressure seal to the vessels.
However, such embodiments have the disadvantage that the cover and/or seal is not permanently attached to the vessel and, therefore, may not be used for the automated handling of vessels comprising the repeated opening and closing of the cap portion without an increased probability of cross-contamination.
Thus, there is a need for providing methods and vessels for the fully automated handling of a liquid comprising more than one tube portion and a means for the handling including the repeated opening and closing of these tube portions in an easy and uncomplicated way.